In food processing, particularly processing of proteinaceous food products, the speed of cooling is exceedingly critical. Failure to cool a food product sufficiently quickly may lead to undesirable effects on the flavor, aroma, texture or other important characteristics of the food product.
There are known various methods for vacuum cooling hot liquids. U.S. Pat. No. 2,996,898 to F. J. Hosken et al. describes a vacuum cooling system for cooling produce that utilizes a refrigerated spray to condense the low pressure steam emanating from the produce. The system includes a liquid reservoir therein containing a liquid coolant supply. Refrigerant coils are immersed in the liquid coolant to produce more efficient heat transfer and prevent buildup of a block of ice on the coils.
U.S. Pat. No. 5,928,699 to Reznik, the disclosure of which is incorporated herein by reference, provides an improved rapid vacuum cooling system. The system comprises a housing, a hot fluid coil disposed in the housing through which flows a hot product, a cooling liquid disposed in the housing which fully covers the hot fluid coil, a vacuum pump operatively connected to an interior of the housing for reducing pressure in the housing until the cooling liquid boils and forms vapors, and a condensing coil disposed in the housing through which flows a cold fluid, the condensing coil condensing the vapors of the cooling liquid and thereby heating the cold fluid. The hot product transfers heat to the cooling liquid, helping it to boil.